In this May 10, 2017 file photo, Sen. Ted Cruz, R-Texas., questions witnesses during a Senate Judiciary Committee hearing on Capitol Hill in Washington. Cruz says an aide was responsible for the “like” that caused a pornographic post to briefly appear on Cruz’s Twitter feed overnight. (AP Photo/Cliff Owen)

WASHINGTON – Republican opposition to the GOP health care bill swelled to near-fatal numbers Sunday as Sen. Susan Collins all but closed the door on supporting the last-ditch effort to scrap the Obama health care law and Sen. Ted Cruz said that “right now” he doesn’t back it.

White House legislative liaison Marc Short and Sen. Lindsey Graham, R-S.C., one of the measure’s sponsors, said Republicans would press ahead with a vote this week. But the comments by Collins and Cruz left the Republican drive to uproot President Barack Obama’s Affordable Care Act dangling by an increasingly slender thread.

A showdown must occur this week for Republicans to prevail with their narrow Senate majority. Next Sunday, protections expire against a Democratic filibuster, bill-killing delays that Republicans lack the votes to overcome.

Already two GOP senators, Rand Paul of Kentucky and John McCain of Arizona, have said they oppose the legislation. All Democrats will vote against it. “No” votes from three of the 52 GOP senators would kill the party’s effort to deliver on its perennial vow to repeal “Obamacare” and would reprise the party’s politically jarring failure to accomplish that this summer.

Collins cited the bill’s cuts in the Medicaid program for low-income people and the likelihood that it would result in many losing health coverage and paying higher premiums. The Maine moderate also criticized a provision letting states make it easier for insurers to raise premiums on people with pre-existing medical conditions.

“It’s very difficult for me to envision a scenario where I would end up voting for this bill,” said Collins.

The conservative Cruz also voiced opposition, underscoring the bill’s problems with both ends of the GOP spectrum.

“Right now, they don’t have my vote,” Cruz said at a festival in Austin, Texas. He suggested the measure doesn’t do enough to reduce premiums by allowing insurers to sell less comprehensive coverage than Obama’s law allows.

The growing opposition leaves the White House and party leaders desperate to rescue their promise to repeal Obama’s law with one immediate option: changing opponents’ minds.

Republicans have said they’re still reshaping the bill in hopes of winning over skeptics. Collins said sponsors were making last-minute adjustments in the measure’s formulas for distributing federal money to states.